Well I am in the middle of moving and had to take apart everything. I had a good size indoor pond with DIY filters that worked great. I am trying to plan ahead for an out door pond. My filter is a 55 gallon barrel. I pump water from the pond to the top of the barrel and it runs over filter mats and scrubbies. So its a wet/dry filter. The water re enters through a 1in pipe in the bottem. What I want to do is add a spillway. I dont know if there is enough pressure coming out of the filter to fill up the spillway without the barrel overflowing. Just thought I would through it out there while I was thinking of it.